Development 2S~V Translocation Chromosomes Carrying Ppd-B1 Locus

Aegilops variabilis is an important genetic resource for wheat improvement.In our previous study,wheat-Ae.variabilis 2S^v（2B）and 2S^v（2D）substitution lines and 2S^vaddition lines were created by distant hybridization between Aegilops variabilis AS116（UUS^vS^v）and common wheat Yiyuan No.2.Phenotypic analysis revealed that the 2S^vchromosome may carry stripe rust resistance gene（s）and high grain iron and zinc content gene（s）.However,substitution lines showed significantly delayed heading time,and tenacious glume,which may be caused by the Ppd1 and Tg homologous genes on 2S^vrespectively.In this study,we induced 2S^vand 2B recombination by using ph1b as tool for chromosome engineering technology.The expected 2S^vrecombinants harbored a small fragment of 2B carrying Ppd-B1 locus.It will be used to explore whether the modified 2S^vchromosome can be directly used for breeding in our further study.The main research results are as follows:（1）The analysis of agronomic traits in greenhouse showed that the heading date of 2S^v（2B）and 2S^v（2D）substitution lines were significantly later than Yiyuan No.2.The average heading time of 2S^v（2B）,2S^v（2D）and Yiyuan No.2were 51.21 days,62.48 days,and 42.79 days,respectively.The two substitution lines were tenacious glume while Yiyuan No.2 were soft glume.The introduction of 2S^vchromosomes into common wheat had no siginificant adverse effects on plant height,spike length,and spikelet numbers.Therefore,the delayed heading and tenacious glume are the main adverse effects of 2S^vintroduction into wheat.（2）Two screening populations were constructed for 2S^v/2B recombinants induced by ph1b using 2S^v（2B）substitution lines WJN2890 and SM830Ph1ph1b as parents.The first population was generated by pollinating SM830Ph1ph1b with WJN2890 and the second population was the reciprocal cross.Twenty-four primary recombinants were obtained by molecular markers and eight confirmed by in situ hybridization.There are eighteen recombinants with one translocated chromosomes,which configuration were 2BS.2BL-2S^vL（3）,2BS-2S^vS.2S^vL（3）,2S^vS-2BS.2BL（7）,2S^vS.2S^vL-2BL（4）,and2BS.2S^vL-2BL（1）.There are two recombinantion lines have two translocated chromosomes which configuration were 2BS.2BL-2S^vL with 2BS-2S^vS.2S^vL and 2S^vS.2S^vL-2BL with 2BS-2S^vS.2S^vL and 2BS-2S^vS.2S^vL with 2S^vS.2BL.Three lines with Robertsonian translocation chromosome 2S^vS.2BL formed by centromere"break-fusion"were also obtained.（3）A 2S^v/2B specific KASP marker 2091R1 for the wheat/Ae.variabilis photoperiod gene Ppd-2S^v/Ppd-B1 was developed.Combining 2091R1molecular marker and in situ hybridization analysis,nine 2S^v/2B secondary translocations carrying Ppd-B1 locus were identified.Among them,five lines carrying 2S^vS-2BS^Ppd-B1-2S^vS.2S^vL-2BL chromosome,one line with2S^vS-2BS^Ppd-B1-2S^vS.2S^vL chromosome,one line with 2S^vS-2BS^Ppd-B1.2BL-2S^vL-2BL chromosome and two lines with 2S^vS-2BS^Ppd-B1.2BL-2S^vL chromosome.In summary,we have generated a number of primary and secondary recombinants of 2S^vand 2B chromosomes.We selected out nine secondary recominants with the chromosome segment of 2S^vcontaining Ppd gene in 2S^vchromosome replaced with the homoeologous segment from 2B chromosome,these secondary translocation lines may which has potential breeding value.